# Electrochemistry to calculate mass of gold required

Submitted by Anonymous (not verified) on Wed, 05/13/2009 - 23:53

A metallurgist wants to goldplate a thin sheet with the following dimensions: 3.8 cm x 21.6 cm x 0.0305 cm. The gold plating must be 50.8 micrometers thick.
(a) How many grams of gold (d=19.3g/cm) are required?
(b) How long will it take to plate the sheet from AuCN using a current of 7.00 A? (Assume 100% efficiency.)

Work out the volume of gold on one side of the sheet by L x B xThickness of plating (not thickness of sheet which can be ignored). Make sure your units are common (cm). Remember that the same volume of gold will be coated on the other side of sheet, so double the volume of gold.

Use density to find the mass of gold.

Then write an equation to show deposition of gold. From the formula, gold ion is Au+. From memory, 1F or 95500C will deposit one mole of gold. So work charge needed to deposit the calculated mass of gold
Rearrange Q =It to find the time in seconds, where I=current and Q=charge